1. Field of the Invention
The present invention relates to an on-vehicle electronic apparatus and, more particularly, to a car navigation apparatus that uses a wireless LAN.
2. Description of the Related Art
In recent years, an automobile which comprises an obstacle detection/warning device has been proposed. As an example of such automobile, ultrasonic sensors are provided to the front and rear portions of a vehicle so as to detect the distances between vehicles and to detect any obstacle.
Each ultrasonic sensor radiates ultrasonic pulses, and receives a wave reflected by any obstacle, thereby detecting an obstacle. Furthermore, by measuring the time required until the reflected wave is received, the distance to the obstacle can be measured.
Upon detection of an obstacle, an audible warning is generated or a warning dialog is displayed to issue a warning to the driver (e.g., see Jpn. Pat. Appln. KOKAI Publication No. 2000-330637).
On the other hand, a car navigation system that mounts a GPS (Global Positioning System) has been developed. Such car navigation system can display information associated with car navigation such as a travel history or the like on a map, and can download and update map information from a server connected to the Internet using a line of a portable phone attached to the car navigation system.
The user can reach a destination by referring to information associated with car navigation such as a travel history or the like on the map, which is displayed on the display screen of the car navigation system (e.g., see Jpn. Pat. Appln. KOKAI Publication No. 2002-221430).
However, since the conventional obstacle detection/warning device uses ultrasonic sensors to detect any obstacle, the detection range of such sensor is narrow, and that device cannot effectively avoid collision between vehicles with a sufficient time margin.
The conventional car navigation system can navigate the driver of a vehicle by its navigation function, but cannot effectively avoid collision or the like.